X-Ray Exam: Ankle

What It Is

An ankle X-ray is a safe and painless test that uses a small amount of radiation to make an image of the ankle. The ankle joint is made up of the ends of the leg bones (tibia and fibula) and the bones in the back part of the foot (tarsal bones).

An X-ray machine sends a beam of radiation through the ankle, and black and white images of the bones and soft tissues are recorded on a computer or special X-ray film. Dense structures that block the passage of the X-ray beam through the body, such as bones, appear white. Softer body tissues, such as the muscles, allow the X-ray beams to pass through them and appear darker.

An X-ray technician in the radiology department of a hospital or a health care provider's office takes the X-rays. Three different pictures are taken: one from the front (anteroposterior view, or AP) of the ankle, one from the side (lateral view, or lat), and one at an angle (internal oblique or mortise view).

Why It's Done

An ankle X-ray can help find the cause of symptoms such as pain, tenderness, and swelling, or deformity of the ankle joint. It can detect broken bones or a dislocated joint. After a broken bone has been set, an X-ray can help determine whether the bones are in proper alignment and whether they have healed properly.

If surgery is required, an X-ray can help in planning the procedure and to assess the results after it. Also, an X-ray can help to detect cysts, tumors, later stage infections, fluid in the joint, and other diseases in the bones of the ankle.

Depending on the results of the ankle X-ray, a follow-up radiology test like a CAT scan or MRI might be needed. These can give different types of information to a doctor when determining the treatment plan.

Preparation

An ankle X-ray doesn't require any special preparation. Your child may be asked to remove clothing, jewelry, or any metal objects that might interfere with the image.

Developing babies are more sensitive to radiation and are at more risk for harm, so if your daughter is pregnant, be sure to tell her doctor and the X-ray technician.

Procedure

This is a quick procedure. Although it may take about 15 minutes or longer, actual exposure to radiation is usually less than a second.

Your child will be asked to enter a special room where X-rays are done, which will most likely contain a table and a large X-ray machine hanging from the ceiling. Parents are usually able to go into the room with their child to provide reassurance. If you stay in the room while the X-ray is being done, you'll be asked to wear a lead apron to protect certain parts of your body. Your child's reproductive organs will also be protected with a lead shield.

If your child is in the hospital and can't easily be brought to the radiology department, a portable X-ray machine can be brought to the bedside. Portable X-rays are sometimes used in emergency departments, intensive care units (ICUs), and operating rooms.

The technician will position your child on the table, and will then step behind a wall or to an adjoining room to operate the machine. Three X-rays are usually taken (from the front, side, and at an angle), so the technician will return to reposition the ankle for each X-ray. Occasionally doctors request an X-ray of the opposite ankle for comparison.

A stress X-ray may also be done to check how tightly the ligaments are holding the ankle together. To do this, the doctor or technician stretches the ankle joint while the X-ray is taken to see if the pressure moves the bones apart.

Older kids will be asked to stay still for a few seconds while the X-ray is taken; infants may require gentle restraint. Keeping the ankle still is important to prevent blurring of the X-ray image.

What to Expect

Your child won't feel anything as the X-ray is taken. The X-ray room may feel cool, due to the air conditioning used to maintain the equipment.

The positions required for the X-rays may feel uncomfortable, but they only need to be held for a few seconds. If your child has an injury and can't hold the required position, the technician might be able to find another position that's easier on your child. Some patients may need medication to relieve the pain a bit before an X-ray is taken. Babies often cry in the X-ray room, especially if they're restrained, but this won't interfere with the procedure.

After the X-rays are taken, you and your child will be asked to wait a few minutes while the images are processed. If they're blurred or unclear, the X-ray may need to be redone.

Getting the Results

A radiologist, a doctor specially trained in interpreting X-ray images, will look at your child's X-rays and send a report to your doctor, who will discuss the results with you.

In an emergency, the results of an X-ray can be available quickly. Otherwise, results are usually ready in 1-2 days. In most cases, results can't be given directly to the patient or family at the time of the test.

Risks

In general, X-rays are safe. Although there's some risk to the body with any exposure to radiation, the amount of radiation used in an ankle X-ray isn't considered dangerous. It's important to know that radiologists use the minimum amount of radiation required to get the best results.

Developing babies are more sensitive to radiation and are at more risk for harm, so if your daughter is pregnant, be sure to tell her doctor and the X-ray technician.

Helping Your Child

You can help your child prepare for an ankle X-ray by explaining the test in simple terms before the procedure. It may help to explain that getting an X-ray is like posing for a picture.

You can describe the room and the equipment that will be used, and you can reassure your child that you'll be right there for support. For older kids, be sure to explain the importance of staying still while the X-ray is taken so it won't have to be repeated.

If You Have Questions

If you have questions about the X-ray, speak with your doctor. You can also talk to the X-ray technician before the procedure.